ATI RN
Endocrine System Questions and Answers PDF Questions
Question 1 of 5
Secretion of which hormone would be increased in an iodine-deficiency goiter?
Correct Answer: A
Rationale: In iodine-deficiency goiter, low iodine reduces thyroxine (T₄) and T₃ synthesis, prompting the pituitary to increase TSH (thyroid-stimulating hormone) to stimulate the thyroid, causing enlargement (goiter). Thyroxine and T₃ decrease due to substrate lack, not increase. 'All' is incorrect only TSH rises to compensate. TSH's feedback-driven surge distinguishes it, key to goiter pathology, unlike diminished thyroid hormones.
Question 2 of 5
An expectant mother tells the nurse that she is concerned about breastfeeding and asks the nurse how her body knows that it is time to produce milk. The nurse's best response regarding stimulus for milk production is that delivery of the fetus:
Correct Answer: A
Rationale: Delivery of the fetus triggers events increasing prolactin levels placental expulsion drops progesterone/estrogen, relieving anterior pituitary inhibition, boosting prolactin for milk synthesis. Oxytocin, also rising, aids ejection, not production. Estrogen drops post-delivery, not rapidly increasing high levels suppress lactation. Prolactin's surge, driven by hormonal shifts and suckling, distinguishes it, key to lactogenesis, unlike ejection or estrogen dynamics.
Question 3 of 5
A small molecule binds to a G protein, preventing its activation. What direct effect will this have on signaling that involves cAMP?
Correct Answer: B
Rationale: G proteins activate adenylyl cyclase in cAMP signaling, converting ATP to cAMP to amplify signals (e.g., epinephrine response). Blocking G protein prevents this activation, halting cAMP production. Hormone binding occurs upstream, excessive cAMP or phosphorylation would require activation. This inhibition distinguishes the direct effect, key to understanding second messenger disruptions in cellular signaling pathways.
Question 4 of 5
Iodide ions cross from the bloodstream into follicle cells via
Correct Answer: C
Rationale: Iodide enters thyroid follicle cells via active transport, using the sodium-iodide symporter (NIS), against its gradient, powered by sodium's electrochemical gradient. Simple diffusion lacks a carrier, facilitated diffusion doesn't use energy, and osmosis moves water. Active transport's energy dependence distinguishes it, essential for thyroid hormone synthesis, concentrating iodide for T3/T4 production.
Question 5 of 5
The gonads produce what class of hormones?
Correct Answer: C
Rationale: Gonads (ovaries, testes) produce steroid hormones estrogens, progesterone, testosterone from cholesterol, acting intracellularly to regulate reproduction. Amine hormones (e.g., thyroid) derive from tyrosine, peptides (e.g., insulin) from amino acids, and catecholamines (e.g., epinephrine) from adrenal medulla. Steroid's lipid-based nature distinguishes gonadal output, critical for sexual development, contrasting with other chemical classes.